President Yeltsin's dismissal of Prime Minister Yevgeny Primakov has cast Russia into a new period of political instability.

The State Duma, Russia's lower house of parliament, is debating whether to impeach the president and both parliamentary and presidential elections are imminent.

The country will be without a prime minister for some time - and it seems unlikely that the Duma will approve the candidate Mr Yeltsin nominates for the post. So how will events develop?

Viktor Chernomyrdin was sacked last March ...

Eight months ago, Russia was in political turmoil. President Yeltsin had just dismissed his Prime Minister, Sergei Kiriyenko, and the Duma, had twice exercised its right to reject Mr Yeltsin's nominee to be the new Prime Minister, Viktor Chernomyrdin.

Yevgeny Primakov stepped in as a compromise candidate and a tense situation was defused.

Now, Mr Yeltsin has triggered another bitter confrontation with the Communist-dominated parliament, by sacking Mr Primakov, the figure of consensus.

All eyes on the Duma

The move was evidently intended as a pre-emptive strike against the Duma, which is discussing whether to start impeachment proceedings against the president.

It shows that this time, Mr Yeltsin is not in a mood for compromise and wants a fight with the opposition.

... closely followed by Sergei Kiriyenko, who lasted until August 1998

All attention will now centre on the Duma.

There are five possible articles of impeachment but only one, accusing Mr Yeltsin of committing a crime by ordering the military intervention in Chechnya, has any likelihood of being approved - a two thirds majority (300 votes) is required.

Even if that article - or any of the five - is approved, it is still highly unlikely that Mr Yeltsin will actually be impeached because the constitutional procedure is heavily weighted in his favour.

But the opposition will have scored an important psychological victory over the president and he will lose the right to dissolve parliament, while the process is underway.

'The biggest mistake'

Even if the impeachment vote fails, the Duma will have a second chance to defy Mr Yeltsin, when his chosen candidate for Prime Minister, Sergei Stepashin, comes before them for confirmation.

The Duma's Communist speaker, Gennady Seleznyov, has already described the dismissal of Mr Primakov as "the biggest
mistake" yet made by the president, and hinted strongly that the Duma will reject Mr Stepashin.

Mr Stepashin is the fourth prime minister in just over a year

The Duma has the right to reject the president's nominee
three times. If it comes to that, then the president can dissolve parliament and call early elections, although, with the economic constition as it is, the opposition will feel confident of doing well.

The Duma could simultaneously makes itself immune from dissolution, through approving impeachment procedures, and refuse to approve a prime minister.

In that case, the crisis would enter uncharted constitutional waters, leading to a prolonged stand-off between president and parliament, which could go on until parliamentary elections, due to be held in December.

Mr Yeltsin has become so unpredictable that some Russian commentators are already speculating about more dangerous scenarios in which, for example, he declares a state of
emergency and tries to govern by decree as he did in 1993.

Any move like that would turn a Moscow political fight into a national crisis.